In U.S. Pat. No. 4,637,607, issued Jan. 20, 1978 to James McArthur, there is diclosed an apparatus which is commercially available under the trade mark DYNATRAC and which comprises a prime mover connected to the input of a frictional transmission, the output of which can be connected to various different patient exercise apparatuses for exercising various limbs and body parts of a patient. Such exercising may be for the purpose of testing the patient or for rehabilitation.
There is also commercially available a back exercising apparatus having a seat and a footrest for supporting a patient in a seated position, and force applying means for applying forces to the upper portion of the patient's body about a horizontal axis and about a vertical axis to thereby perform so-called flexion and extension and rotation testing and exercising of the patient's back.